How astrocytes feed hungry neurons |
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Authors: | Luc Pellerin |
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Institution: | (1) Département de Physiologie, Université de Lausanne, Switzerland |
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Abstract: | For years glucose was thought to constitute the sole energy substrate for neurons; it was believed to be directly provided
to neurons via the extracellular space by the cerebral circulation. It was recently proposed that in addition to glucose,
neurons might rely on lactate to sustain their activity. Therefore, it was demonstrated that lactate is a preferred oxidative
substrate for neurons not only in vitro but also in vivo. Moreover, the presence of specific monocarboxylate transporters
on neurons as well as on astrocytes is consistent with the hypothesis of a transfer of lactate from astrocytes to neurons.
Evidence has been provided for a mechanism whereby astrocytes respond to glutamatergic activity by enhancing their glycolytic
activity, resulting in increased lactate release. This is accomplished via the uptake of glutamate by glial glutamate transporters,
leading to activation of the Na+/K+ ATPase and a stimulation of astrocytic glycolysis. Several recent observations obtained both in vitro and in vivo with different
approaches have reinforced this view of brain energetics. Such an understanding might be critically important, not only because
it forms the basis of some classical functional brain imaging techniques but also because several neurodegenerative diseases
exhibit diverse alterations in energy metabolism. |
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Keywords: | Energy metabolism glucose lactate functional brain imaging neurodegenerative diseases neurometabolic coupling |
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